Ceiling fans are fans mounted from the ceiling of a room in a building or from the roof of a covered patio, or the like, and have a housing generally supported from a pipe or pole attached to the ceiling. Ceiling fans typically include a motor coupled to a plurality of fan blades to rotate the fan blades. The rotating fan blades provide airflow, enabling the ceiling fan to provide an energy efficient means of cooling or ventilating an area.
Conventional ceiling fans typically include one of two different types of motors. The first, known in the art as an internal rotor motor is configured such that the rotor is arranged inside the stator and the fan housing and is connected to a shaft extending outside the housing. The shaft is connected to the fan blades, typically through a flywheel and fan blade holders.
The second type of ceiling fan motor is known as an external rotor motor. In an external rotor ceiling fan, the external housing of the motor is the rotor or is directly attached to the rotor so that the external housing of the fan rotates with the rotor. The external housing spins around the stator, and fan blades attached to the rotor, generally by fan blade holders, rotate to generate airflow.
During operation of a fan, vibrations are produced by the rotating fan blades and by the motor. These vibrations are transferred between the blades and the motor through the connection therebetween. In some instances, the vibrations can become significant, resulting in additional noise and, in extreme cases, damage to the fan or motor.
One solution to reduce vibrations is to provide a rubber pad between the rotor and the fan blades or the fan blade holders. This rubber pad, however, provides only minimal reduction in the vibrations since the pad is connected directly to both the fan blade holders and the motor. Additionally, the screws connecting the motor housing to the fan blade holders are directly connected to the motor housing and the fan blade holders, and therefore vibrations are transferred between the motor and fan blades through the screws.
It would thus be desirable to provide a system to reduce vibrations in external rotor ceiling fans.